Siemens Sinumerik 840D sl Programming Manual page 330

Coordinate transformations (frames)
13.7 Programmable mirroring (MIRROR, AMIRROR)
Examples
Example 1: Milling
Program code
N10 G17 G54
N20 L10
N30 MIRROR X0
N40 L10
N50 AMIRROR Y0
N60 L10
N70 MIRROR Y0
N80 L10
N90 MIRROR
N100 G0 X300 Y100 M30
330
The contour shown here is programmed once
as a subprogram. The three other contours are
generated using mirroring. The workpiece zero
is located at the center of the contours.
Comment
; Working plane X/Y, workpiece zero
; Machine first contour at top right
; Mirror X axis (the direction is changed in X)
; Machine second contour at top left
; Mirror Y axis (the direction is changed in Y)
; Machine third contour at bottom left
; MIRROR resets previous frames. Mirror Y axis (the di-
rection is changed in Y)
; Machine fourth contour at bottom right
;Deactivate mirroring
; Retraction, end of program
Programming Manual, 01/2015, 6FC5398-1BP40-5BA2
Fundamentals